SCIENCE OF THE NORTHERN LIGHTS

 By John Bennett

The Northern Lights have always captured man’s imagination and as our last blog depicted, there are many myths and legends surrending them.

As far as science was concerned though, it took a very long time for man to uncover the scientific truth behind the Northern Lights.

Galileo first used the term boreal aurora (later changed to Aurora Borealis) after Aurora, the Roman goddess of dawn. However it was a Norwegian scientist named Kristian Birkeland who set out to achieve what many before had tried and failed: to solve the mystery of the Northern Lights.  To Birkeland, the Lights represented the threshold between the visible and invisible worlds; the link between the planet and the mysterious forces that shaped the universe.  However in the late 19th Century the prevailing belief was centred on Aristotle’s assertion that there could be no interaction between the heavens and the Earth because the heavens were perfect and unchanging.  This resolute popular conviction created a difficult climate for Birkeland’s propositions.

In the winter of 1899 Birkeland spent five months isolated in a mountain-top observatory at Kaafjord in the far north of Norway, a position known as having the most sightings of the Lights.  Eventually he discovered that the force disturbing the magnetic field came directly from the sun in narrow, high-velocity beams of negatively charged particles (electrons) called cathode rays.  Sometimes these active particles hit the magnetic field of the Earth and followed the field lines down towards the poles, where they struck atoms in the atmosphere.  The energy created by the collisions was emitted as light.  The lights only appeared during magnetic storms because the cathode rays from the sun were moving beams of electrons, creating electric currents that, in turn, made their own magnetic fields.

Birkeland’s conclusions were published in 1901 and Norwegian newspaper headlines trumpeted,  “Riddle of the Aurora solved!”  However the international scientific community was not so impressed.  Britain was the global leader in science and would not shift from her resolute opinion that space was an empty vacuum.  Birkeland’s findings were rejected.  He was bitterly disappointed but even more determined to prove his theory The Norwegian government refused him any more funding, so he had to raise the money himself.  This he did through the invention of a fertiliser (of which there was a chronic global shortage at the time) using electromagnetic furnace technology.  Birkeland continued his fanatical study of the Lights over the following years and in 1908 published his monumental work, “The Norwegian Aurora Polaris Expedition 1902-1903” describing his second, bigger expedition to the far north. But again the scientific community was disparaging of his ideas and he suffered another major blow. 

Gradually over the five years following this second disappointment, his life began to crumble.  His work was overshadowed by other scientific developments at the time, such as Einstein’s theory of relativity and Bohr’s model of the atom.  His obsessional relationship with his work drove his wife to leave him.  He was also growing increasingly dependent on alcohol and the sedative veronal, and his health began to deteriorate.

He spent his final years in Egypt studying the Zodiacal Light. A combination of insomnia, whisky and veronal fuelled chronic paranoia.  He became convinced that with the outbreak of war, one of his inventions, the electromagnetic cannon, placed him in danger.  He kept the copies of his patent in a specially installed safe in his room, bought two guard dogs and three guns and sacked his servants as he was convinced were plotting against him. 

On the 16th June 1919, aged just 49,Kristian Birkeland was found dead in a hotel room. The post-mortem revealed him to have taken 10g of veronal the night of his death, instead of the 0.5g recommended dose.

For 50 years after his death, Birkeland’s reputation sank into oblivion.  In 1970 space satellites found incontrovertible evidence of a flow of electric particles from the sun.  This proved that “empty space” was actually not empty at all, but filled with electrified gas, which then forms “solar wind”, which Birkeland had identified more than 60 years earlier.  Today he is credited as the first scientist to propose an essentially correct explanation of the Aurora Borealis.